What is the best estimate of weight a medium sized dog?

It's impossible to give a "best estimate" for the weight of a medium-sized dog without more information. "Medium-sized" is very subjective and can vary greatly depending on breed, age, and individual variation.

Here's why a general estimate is unhelpful:

* Breed differences: A medium-sized Labrador Retriever will be much heavier than a medium-sized Beagle.

* Age: Puppies grow rapidly and reach their full weight as adults.

* Individual Variation: Even dogs within the same breed can have significant weight differences.

To get a better estimate, you'll need to consider the dog's breed, age, and overall build. If you are looking for a specific estimate, I recommend checking reputable dog breed websites or consulting with a veterinarian.